Ethical questions become easier if you assume that all actions are intentional and made with full knowledge of the consequences. Unfortunately real people are biological organisms that may shed pathogens wherever they go. Your mere presence may be enough to harm other people, without your intention or knowledge.
Should we as a society allow people to endanger bystanders, if the known preventative measures cause more harm than good to the person taking them? Or should we require everyone to follow the best practices, if the benefits to the society sufficiently outweigh the harm to the individual?